Matlab matrix syntax weird

Hello!

I am a newby to Matlab, and I have a small code fragment I cannot understand.

I need to know what the following lines do, but even trying to visualize them in Matlab, I was not able to find out the meaning:

p(:, :, 1)=u(:, [2:width, width])

p(:, :, 2)=u([2:height, height], :)

p(:, :, 1)=p(:, :, 1)

Can you please explain what those the above lines mean?

Thank you.

Answer 1

[Star Strider]

It is likely easiest to assign a value to ‘height’ and ‘width’ and see the result —

height = 4;                                     % Create VAlue
width  = 5;                                     % Create Value
u = randi(9,height,width)                       % Create Matrix

u = 4×5

6 7 1 8 2 8 3 1 9 1 4 2 3 1 6 1 8 4 5 8

p(:, :, 1)=u(:, [2:width, width])

p = 4×5

7 1 8 2 2 3 1 9 1 1 2 3 1 6 6 8 4 5 8 8

p(:, :, 2)=u([2:height, height], :)

p = 
p(:,:,1) =

     7     1     8     2     2
     3     1     9     1     1
     2     3     1     6     6
     8     4     5     8     8


p(:,:,2) =

     8     3     1     9     1
     4     2     3     1     6
     1     8     4     5     8
     1     8     4     5     8

p(:, :, 1)=p(:, :, 1)                               % This Is Obviously Redundant, Since It Assigns The First Page To The First PAge

p = 
p(:,:,1) =

     7     1     8     2     2
     3     1     9     1     1
     2     3     1     6     6
     8     4     5     8     8


p(:,:,2) =

     8     3     1     9     1
     4     2     3     1     6
     1     8     4     5     8
     1     8     4     5     8

.